Driving devices and retraction devices for fixing means of the above type are known in several embodiments.
Driving devices are described in e.g. SE 431 053 B and SE 535 531 C2. The driving device of said first publication operates satisfactory, but has a relative complex construction and the handling thereof is circumstantial. The driving device of said latter publication also operates satisfactory and has also a less complex construction. It comprises a driving means which to a great extent is similar to a screw. The driving means, which is a separate member, is inserted into the open rear end portion of the sleeve, is brought to engage an internal thread in the sleeve and is further brought to engage a rear portion of the pin in the sleeve, and by continuously screwing the driving means into the sleeve, the pin is driven forward in a driving direction relative to the sleeve and the front end portion of the pin is driven out of through the opening in the sleeve and into the bone material in one of the bone fragments.
Retraction devices are defined in e.g. SE 433 166 B and SE 535 436 C2. The retraction device of said first publication operates satisfactory, but has, as the driving device of the above-mentioned SE 431 053 B, a relative complex construction and the handling thereof is circumstantial. The retraction device of said latter publication also operates satisfactory and has also a less complex construction. It comprises a retraction means which to a great extent is similar to a very short screw with an internal, but not an external threading. The retraction means, which is a separate member, is inserted into the open rear end portion of the sleeve and threaded onto the rear portion of the pin while it at the same time is brought to engage the open rear end portion of the sleeve, and by continuously screwing the retraction means into the sleeve, the pin is pulled or displaced backwards in a retraction direction relative to the sleeve and the retraction means, and the front end portion of the pin is retracted out of the bone material in the bone fragment in question and into the sleeve through the opening therein.
A drawback with these prior art driving and retraction devices is that they consist of separate, relatively small members which are easy to mislay and they can be used only for driving the pin of the fixing means and only for retraction of the pin of the fixing means respectively.